There has recently been a push to require radiotelephone users in vehicles to communicate using a “hands-free” mode for safety purposes. The hands-free mode basically allows a user to communicate over their radiotelephone without having to hold the radiotelephone up to their ear, i.e. without having to use their hands. This leaves the user's hands free to control the vehicle.
There have been several prior art techniques implemented to provide a hands-free operation. Typically, these techniques require a radiotelephone with available audio input/output (I/O) jacks and various accessories to take advantage of available audio I/O in the phone. For example, many radiotelephones include jacks for a microphone and speaker(s). This available audio I/O allows a user to wear a headset containing speakers electrically connected to the speaker jacks of the phone and containing a microphone electrically connected the microphone jack. In this way, the headset coupled with the audio I/O of the radiotelephone allows hands-free operation of the phone. However, this technique requires the purchase of the headset which adds significant cost. In addition, a user must still place the headset on their head when communicating, which negates some of the hands-free benefit, and the use of many wires could be cumbersome for the user to connect.
Another prior art technique also uses the audio I/O of a radiotelephone to connect a loudspeaker and high gain microphone which connects directly to the phone. The loudspeaker and microphone can be part of a single module or can be separate. For example, a single loudspeaker/microphone module can be plugged directly into the audio I/O of the phone, and a user can communication without either of the loudspeaker or microphone being located near their head. In addition, the module or individual speaker and microphone can be powered directly from the phone or be self-powered. This technique allows hands-free communication, but still requires the purchase of the audio module which adds significant cost. Moreover, the module must necessarily consume more power as the loudspeaker and microphone are located remotely from the user, requiring more amplification to be heard. In particular, if powered from the phone, the module will reduce battery life and thus talk time of the phone, and if powered separately, a separate battery will need to be purchased which will typically fail a different times than when the phone need recharging, inconveniencing the user.
Another prior art techniques uses wireless techniques to transceiver audio signals between a communication device and an audio device. Such wireless connection can be provided between infrared ports of the communication device and the audio device, or can be provided by radio frequency networks (i.e. local area networks) of several types as are commonly known by the generic or trade names LAN, WLAN, WAP, WiFi, Bluetooth™ and the like, herein collectively referred to as wireless local area networks or WLAN. These wireless techniques all suffer from the need to have a updated radiotelephone capable of LAN communication, and the need to have additional audio hands-free accessories. Unfortunately, many users have older-style phones without WLAN capability. Moreover, users may not wish to purchase such an adapted phone nor the needed WLAN audio accessories to operate in hands-free mode.
Therefore, what is needed is technique to provide a hands-free operational mode for existing radiotelephones without WLAN communication capability. It would also be of beneficial to provide hands-free operation without the need to purchase additional audio accessories. It would also be an advantage to provide this benefit for minimal cost.